import time as t

class MyTimer():
    def __init__(self):
        self.unit = ['年','月','天','小时','分钟','秒']
        self.prompt = '未开始计时！'
        self.lasted = []
        self.begin = 0
        self.end = 0
        
    def __str__(self):
        return self.prompt
    
    __repr__=__str__
    
    def __add__(self,other):
        prompt = '总共运行了：'
        result = []
        for index in range(6):
            result.append(self.lasted[index]+other.lasted[index])
            if result[index]:
                prompt += (str(result[index])+self.unit[index])
        return prompt
    
    #计时开始
    def start(self):
        self.begin = t.localtime()
        self.prompt = '提示：请先调用stop()停止计时！'
        print('计时开始...')
        
    #停止计时
    def stop(self):
        if not self.begin:
             print('提示:请先调用start()进行计时！')
        else:
            self.end = t.localtime()
            self._calc()
            print('计时结束')
            
    #内部方法计算运行时间
    def _calc(self):
        self.lasted = []
        self.prompt = '总共运行了：'
        for index in range(6):
            self.lasted.append(self.end[index]-self.begin[index])
            if self.lasted[index]:
                self.prompt += (str(self.lasted[index])+self.unit[index])
        #为下一轮计时 初始化变量
        self.begin = 0
        self.end = 0
        
